Bellows unit

ABSTRACT

The invention relates to a bellows unit in which expansion of a bellows rotates an output spindle. The spindle is engaged with the bellows via a lever arm formed with recesses at different distances from the spindle. A thrust member is locatable in any recess and engages an end of the bellows, whereby the torque exerted by the bellows on the spindle is adjustable.

United States Patent Bloom [451 Apr. 4, 1972 BELLOWS UNIT [72] Inventor:Joseph Lewis Bloom, Baie DUrfe, Quebec,

Canada [73] Assignee: Joseph Lucas (Industries) Limited, Birmingham,England [22] Filed: Apr. 29, 1970 [21] Appl. No.: 32,821

[51] Int. Cl ..F01b 19/00 [58] Field oiSearch ..92/l3.l, 13.2, 13.4, 39;

[56] References Cited UNITED STATES PATENTS 2,254,539 2/1941 Mattox..92/13.2X

Kogan et al "92/132 X Waite et a1...

3,375,721 4/1968 Joesting ..73/407 FOREIGN PATENTS OR APPLICATIONS1,190,770 10/ 1 959 France ..92/13.2

Primary Examiner-Edgar W. Geoghegan Assistant ExaminerLeslie .l. PayneAttorney-Holman & Stern [57] ABSTRACT The invention relates to a bellowsunit in which expansion of a bellows rotates an output spindle. Thespindle is engaged with the bellows via a lever arm formed with recessesat different distances from the spindle. A thrust member is locatable inany recess and engages an end of the bellows, whereby the torque exertedby the bellows on the spindle is adjustable.

5 Claims, 3 Drawing Figures Patented April 4, 1972 7 3,653,300

I NVE NTOR 0490 51mm.

BELLOWS UNIT This invention relates to a bellows unit and has as anobject to provide a bellows unit in a convenient form.

A bellows unit in accordance with the invention comprises a bellows, anend member on the bellows and movable on expansion and contraction ofthe bellows in response to a pressure difference between the inside andoutside of the bellows, a pivot whose axis is substantiallyperpendicular to the direction of movement of the end member, an armsecured to the pivot and having thereon a contact part formed with aseries of recesses which are spaced at different distances from the axisof the pivot, a thrust member mounted on the end member and movable intolocating engagement with a desired one of the said recesses, and lockingmeans for securing the thrust member relative to the end member, wherebythe moment of the force applied by the bellows to the pivot through theintermediary of the thrust member and the arm may be varied byadjustment of the thrust member.

An example of the invention is shown in the accompanying drawings inwhich:

FIG. 1 is a cross-section through an example of a bellows unit inaccordance with the invention;

FIG. 2 is a fragmentary section on line 22 in FIG. 1; and

FIG. 3 is an exploded perspective view of a part of the unit shown inFIG. 1.

The unit shown includes a housing with a fixed end wall 11 and aremovable end wall 12. Adjustably secured to the fixed and movable endwalls ll, 12 respectively are a pair of bellows supports l3, 14. Thebellows 15, 16 are sealingly attached to the bellows supports l3, 14respectively.

The end of the bellows l5, 16 are attached to opposite ends of an endmember 17. In the arrangement shown the interior of the bellows 16 isevacuated and passages 13a are formed in the bellows support 13 to allowfluid under pressure to enter I the bellows 13. Fluid at a differentpressure is introduced into the housing 10 and the unit is required toprovide an output force which is a function of these two pressures.

The output is extracted from the unit by means of spindle 18 to which anarm 19 is secured. The arm 19 projects into a recess 20 in the side ofthe end member 17. The end of the arm 19 is formed with a recess 21 inwhich a contact member 22 is mounted. The contact member 22 may beformed of a hard synthetic resin material such as nylon, or fromsintered metal. The contact member 22 is basically of channel-shapedconfiguration and its base is formed internally with a series ofrecesses 23 which are spaced by different distances from the axis of thespindle 18.

Co-acting with the contact member 22 is a thrust member in the form ofthe head of a screw-threaded member 24 screwthreadedly engaged with theend member 17. The head of the screw-threaded member 24 is ofdisc-shaped configuration with a rounded periphery which can enter therecesses 23. The end member 17 also has a thrust face which is formedwith a shallow groove 25 extending in the direction of the axis of thescrew-threaded member 24 and the head of the screwthreaded member 24engages in this groove 25. As will be seen from the drawing, therefore,the thrust which is applied to the end member 17 by the bellows istransferred through the head of the screw-threaded member 24 to thecontact member 23 and thence to the arm 19 and the spindle 18. Byselecting a different one of the recesses 23 for engagement with thehead of the member 24 the moment of the force applied to the arm 19about the axis of the spindle 18 can be varied so that the 3 5 lel tothe axis of the spindle.

torque applied to the spindle 18 is likewise varied. A lock nut 26 isprovided on the member 24 for locking this in its adjusted position, adeformable locking washer 27 being provided for preventing rotation ofthe lock nut.

It will be noted that, as well as providing easy adjustment of thebellows unit, the arrangement described above also ensures thatmovements of the member 17 in directions perpendicular to the axes ofthe bellows are prevented in service.

This has the result of reducing the effect of vibration on the bellows,the life span of which is thereby increased.

Having thus described my invention what I hereby claim as new and desireto secure by Letters Patent is:

1. A bellows unit comprising a bellows, an end member on the bellows andmovable on expansion and contraction of the bellows in response to apressure difference between the inside and the outside of the bellows, aspindle whose axis is substantially perpendicular to the direction ofmovement of the end member, an arm secured to the spindle and havingthereon a contact part formed with a series of recesses which are spacedat different distances from the axis of the spindle, a thrust memberscrew-threadedly engaged with the end member for movement in a directionsubstantially perpendicular both to the direction of movement of the endmember and to the axis of the spindle and selectively engageable withany desired one of the said recesses, and locking means for securing thethrust member relative to the end member, whereby the moment of theforce applied by the bellows to the spindle through the intermediary ofthe thrust member and the arm may be varied-by adjustment of the thrustmember.

2. A unit as claimed in claim 1 in which the thrust member is formedwith a head engageable both with the said recesses and with the endmember.

3. A unit as claimed in claim 2 in which the said recesses and the headare formed so as to prevent relative movement between the arm and thecontact member in directions paral- 4. A unit as claimed in claim 3 inwhich the end member is formed with a groove in which the head of thethrust member is located so as to prevent relative movement between thethrust member and the end member in directions parallel to the axis ofthe spindle.

5. A bellows unit comprising a pair of bellows, an end member sealinglysecured to both bellows and movable in response to pressure differencesbetween the insides and the outsides of the bellows, a casingsurrounding the bellows means for introducing a fluid pressure into oneof the bellows, the inside of the said casing being at a differentpressure, a spindle whose axis is substantially perpendicular to thedirection of movement to the under member, an arm secured to the spindleand having thereon a contact part formed with a series of recesses whichare spaced at different distances from the axis of the spindle, a thrustmember screw-threadedly engaged with the end member and movable, in adirection substantially perpendicular to the axis of the spindle, intolocating engagement with any desired one of said recesses the recessesof the end member being formed so that the thrust member in use acts toprevent relative movement between the said end member and the arm in adirection parallel to the axis of the spindle and rocking means forsecuring the thrust member to the end member, whereby the moment of aforce applied by a bellows to the spindle through the intermediary ofthe thrust member and the arm may be varied by adjustment of the thrustmember.

1. A bellows unit comprising a bellows, an end member on the bellows andmovable on expansion and contraction of the bellows in response to apressure difference between the inside and the outside of the bellows, aspindle whose axis is substantially perpendicular to the direction ofmovement of the end member, an arm secured to the spindle and havingthereon a contact part formed with a series of recesses which are spacedat different distances from the axis of the spindle, a thrust memberscrewthreadedly engaged with the end member for movement in a directionsubstantially perpendicular both to the direction of movement of the endmember and to the axis of the spindle and selectively engageable withany desired one of the said recesses, and locking means for securing thethrust member relative to the end member, whereby the moment of theforce applied by the bellows to the spindle through the intermediary ofthe thrust member and the arm may be varied by adjustment of the thrustmember.
 2. A unit as claimed in claim 1 in which the thrust member isformed with a head engageable both with the said recesses and with theend member.
 3. A unit as claimed in claim 2 in which the said recessesand the head are formed so as to prevent relative movement between thearm and the contact member in directions parallel to the axis of thespindle.
 4. A unit as claimed in claim 3 in which the end member isformed with a groove in which the head of the thrust member is locatedso as to prevent relative movement between the thrust member and the endmember in directions parallel to the axis of the spindle.
 5. A bellowsunit comprising a pair of bellows, an end member sealingly secured toboth bellows and movable in response to pressure differences between theinsides and the outsides of the bellows, a casing surrounding thebellows means for introducing a fluid pressure into one of the bellows,the inside of the said casing being at a different pressure, a spindlewhose axis is substantially perpendicular to the direction of movementto the under member, an arm secured to the spindle and having thereon acontact part formed with a series of recesses which are spaced atdifferent distances from the axis of the spindle, a thrust memberscrew-threadedly engaged with the end member and movable, in a directionsubstantially perpendicular to the axis of the spindle, into locatingengagement with any desired one of said recesses the recesses of the endmember being formed so that the thrust member in use acts to preventrelative movement between the said end member and the arm in a directionparallel to the axis of the spindle and rocking means for securing thethrust member to the end member, whereby the moment of a force appliedby a bellows to the spindle through the intermediarY of the thrustmember and the arm may be varied by adjustment of the thrust member.